The changing of the shape and color of hair is an important field in modern cosmetics. As a result, the appearance of the hair can be adapted both to current fashion trends and to the individual wishes of the individual consumer. The fashionable color design of hairstyles or the covering of gray or white hair with trendy or natural color tones typically occurs with color-modifying agents. Apart from a high coloring performance, these agents should have additional properties, such as, for example, the increase in hair volume.
Various coloring systems are known in the prior art for providing color-modifying cosmetic agents, in particular, for the skin or for keratin-containing fibers such as, for example, human hair.
Oxidation dyeing agents are used for permanent, intensive colors with suitable fastness properties. Such dyeing agents customarily include oxidation dye precursors, so-called developer components and coupler components. Under the influence of oxidizing agents or atmospheric oxygen, the developer components form the actual dyes with one another or during coupling with one or more coupler components. The oxidation dyeing agents are characterized by excellent, long-lasting coloring results. For natural-looking colors, customarily a mixture of a relatively large number of oxidation dye precursors must be used; in many cases, direct dyes are used, furthermore, for providing nuances.
Dyeing or tinting agents, which include so-called direct dyes as the coloring component, are customarily used for temporary colors. These are dye molecules that are directly absorbed onto the keratinic fibers and do not require any oxidative process to develop the color. These dyes include, for example, henna which was already known in antiquity for dyeing skin and hair. As a rule, these colors are markedly more sensitive to shampooing than oxidative colors, so that an often undesirable shift in shades or even a visible homogeneous color loss occurs much earlier.
Lastly, a further dyeing method has attracted great interest. In this method, precursors of the natural hair dye melanin are applied to, e.g., hair; these then form bioanalogous dyes in the course of oxidative processes in the hair. 5,6-Dihydroxyindoline, for example, is used as the dye precursor in a method of this kind. Particularly in the case of the repeated use of agents which include 5,6-dihydroxyindoline, it is possible to restore the natural hair color in persons with gray hair. Coloring can occur here with atmospheric oxygen as the sole oxidizing agent, so that other oxidizing agents need not be used. In persons originally having medium-blond to brown hair, 5,6-dihydroxyindoline can be used as the sole dye precursor. For use in persons having an originally red and in particular dark to black hair color, in contrast, satisfactory results can often be achieved only by the concurrent use of further dye components, in particular special oxidation dye precursors.
However, the oxidative dyeing agents known in the prior art do not always lead to the desired high coloring performance, in particular to a high color depth.
Accordingly, it is desirable to provide a cosmetic agent for dyeing keratinic fibers, which avoids or at least reduces the disadvantages of the prior art and which results in an improved color depth. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with this background of the invention.